Multi Commander Support Forum

Multi Commander => Support and Feedback => Topic started by: Suncatcher on November 08, 2016, 18:19:34

Title: MD5 calculation
Post by: Suncatcher on November 08, 2016, 18:19:34

Does Create MD5 checksums file in File Checksum menu use filename-dependent hash-function?
I tried it on technically similar files (which have different names) and it calculated different checksums for them.
I assume, MD5 should behave other way.

Title: Re: MD5 calculation
Post by: Mathias (Author) on November 08, 2016, 18:26:07

Filename make no difference.   the hash is built on the file content.
It is used to verify that files are identical and have not changed.

Title: Re: MD5 calculation
Post by: Suncatcher on November 08, 2016, 19:10:17

Quote

Filename make no difference

However, I get contradictory statements about this in the web. They say it depends on the MD5 implementation (http://stackoverflow.com/questions/5055143/will-changing-a-file-name-affect-the-md5-hash-of-a-file), and which implementation is used by MC?
I also tried CertUtil command utility by MS and it also gave me different checksums.

Title: Re: MD5 calculation
Post by: Mathias (Author) on November 08, 2016, 22:15:09

No. The hash is built on the content.. The filename does not matter. it is not used when calculating the hash. 
MD5 is just an algorithm to calculate a hash. checksum files are using it for matching content.
You can calculate the hash of the filename if you want. But it is pointless for checksum files

Title: Re: MD5 calculation
Post by: Suncatcher on November 09, 2016, 13:45:19

Yeah, that's it. Some of the contents were different.